Well cleaning system



March 9, 1937. c. H. SWEET WELL CLEANING SYSTEM Filed June 1-7, 1935 Fatente Mar. 9, 1937 0 STATE PATENT OFFICE- WELL CLEANING SYSTEM Cecil H. Sweet, Brea, Calif., assignor to John Grant, Los Angeles, Calif.

Application June 1'2, 1935, Serial No. 26,912

15 Claims.

This invention has to do generally with Well cleaning devices and is more particularly concerned with such devices wherein there is provided a low-pressure or charge-receiving chamber with a normally closed inlet adapted to be opened at predetermined points in the well, whereby the well fluid, under relatively high pressure, charges section of the perforated casing being cleaned,

from the surrounding formation; that is to say, there is induced a cross flow, as distinguished froirimowin a vertical direction, through the well sands into the perforations. The present systom retains this characteristic feature as regards the induced flow of well fluid. through the formation, but combines therewith an added feature and improvement giving rise to an operating (sand flushing) condition not present in prior well cleaning systems orldevices, so that not only is the efiiciency of the perforation cleaning operation improved, but also the porosity of the formation sands and productiveness of the well, are greatly increased. Thus, one of my principal ob- 3 j ects is to provide a system for cleaning the casing perforations, and at the same time to thoroughly flush the interstitial spaces of the sands in the surrounding formation. In accordance with the invention, this object is accomplished by inducing in additon to a horizontal flow of well fluid through the formation into the casing perforations, a circulation of flushing fluid through the sands in a generally vertical, preferably downward, direction. In thismanner. the interstitial spaces in the formation sands are subjected to a very effective washing action occurring simultaneously with the induced flow through the casing perforations.

The invention in its preferred form, provides for the maintenance of an hydraulic column within the pipe on the lower end of which the apparatus is lowered in the casing, and a valvular control whereby simultaneously with the opening of the charge receiving chamber, the hydrostatic column so maintained is permitted to flow outwardly through the casing perforations into the formation above the particular section being cleaned, and then downwardly through the sands around the said section in a direction generally crosswise to the laterally flowing well fluid being drawn through the casing perforations. After being drawn downwardly through the sands around the casing by the induced suction, the flushing fluid from the hydrostatic column is taken in through the casing perforations along with the well liquid.

The invention embodies numerous additional features of operation, as well as further objects and details in connection with a preferred form of apparatus for performing the cleaning operation as described above. All these, however, will be fully uiiderstood from the following detailed description of the invention in one of its typical and preferred forms.

Reference is had throughout the description to the accompanyinug drawing, in which:

Fig. 1 is a longitudinal sectional view of the apparatus showing the bailer lowered to a position above the valve;

Fig. 2 is a view similar to- Fig. 1, showing the positions of the parts after the bailer closure has been opened;

Fig. 3 is a sectional view illustrating a typical form of bailer; and

Fig. 4 is a section on lines 4-4 of Fig. 1.

In the drawing, I have shown a tubular assembly generally indicated at H), lowered within the well casing H on the lower end of a pipe string I2 which, as will be understood, extends upwardly within. the casing to the ground surface. Generally speaking, the purposes of the tubular assembly Ill are to form a confined zone within a particular section of the perforated casing to be cleaned in order that upon opening the bailer closure, as will hereinafter appear, intense and localized pressure differential may be applied to the casing perforations l3 surrounding that zone; and also to provide a means in the nature of an abutment capable of coacting with the bailer to open the bailer closure and thereby induce an inward flow of well fluid through the casing perforations l3. It may be mentioned at this point that well cleaning systems involving the use of a tubular assembly or abutment adapted to be lowered to predetermined position within the casing in advance of a bailer containing a charge receiving chamber, broadly constitute the subject matter of a copending application Ser. No. 26,916, filed June 17, 1935 by John Grant on Well cleaning system.

The assembly I 8 comprises a tubular body I4 connected at its upper end by coupling I5 with the pipe string I2 and carrying on its lower end a screwthreaded shoe I6. The body I4 carries a pair of packers I] and I8 at conveniently spaced points, the packers having substantially fluid tight engagement with the casing II and forming a confined annular spacing I9 around the upper portion of the body. I preferably, although not always necessarily, provide a third packer 28 at a distance below packer I8 so as to confine a second annular space 2| around the lower portion of the body. It will be understood of course that the packers may be of any suitable construction and may be mounted on the body in any convenient manner. As a typical illustration, each packer assembly is shown to comprise a cup-shaped supporting member 22 containing a cup leather or rubber 23, hearing against the casing, members 22 and 23 of the several packers being clamped together and held in predetermined spaced arrangement by spacer sleeves 24, 25, 25 and 21 placed around the body I4 and clamped between coupling I5 and shoe I6, as illustrated.

In order to facilitate raising and lowering the assembly I8 within the well liquid standing in the casing I I, and to overcome the fluid resistance that would otherwise be offered by reason of the close engagement between the packers of the wall of the casing, suitable means may be provided for by-passing the well liquid around or past the several packers. As a convenient means for forming the by-pass, insert within the body I4 a tube 28 bearing terminally against coupling 85 and shoe I6, and having, as shown in Fig. 4 opposite flattened surfaces 29 forming by-pass' passages 38 extending longitudinally from ports 3I in body I4 and spacer sleeve 21 above packer I1, to similarly arranged ports 3I at points below the lowermost packer 20. Thus as the assembly I is lowered within the casing, the well fluid by-passes the packers by flowing relatively upwardly through passages '30, and oppositely during withdrawal of the apparatus from the well.

Within the lower interior of tube 28 is inserted a tubular liner 33, to the upper end of which is threaded at 34 an upwardly projecting disk breaking member 35, the latter having a reduced diameter portion 36 with a toothed upper end 31 adapted to engage and break the bailer disk, as will presently appear. A seat 38 for the ball check valve 39 is screwed into the lower end of member 35, valve 38 rising from its seat to permit the upward flow of fluid through the disk breaking member into the bailer during the cleaning operation. A valve seat 4I having an upwardly tapered bore 42 and shoulder at 43 is clamped in position above the disk breaking member 36, between liners and 45.

A tubular valve 46 having a tapered seating surface 46a and an inwardly beveled upper. end

surface 46b controls the passage of fluid through ports 41 extending through the valve seat 4|, tube 28, body I4 and spacer sleeve 26. The valve is normally supported and held in its closed position of Fig. 1 by coil spring 48 seating at its lower end on the disk breaking member 35. Valve 46 is capable of downward movement against the resistance of spring 48 and in telescoping relation to the disk breaking member 36, sufficiently to place space I9 via ports 4] in open communication with space 48 and the interior of the pipe string I2.

The cleaning operation involves the application of a sudden and violent suction or pressure differential to the casing perforations. I3 between packers I8 and 20, via body passage 50, ports and the surrounding space 2|. Such pressure differential preferably is obtained by lowering within the pipe string I2 'a device, such as a bailer, having a normally closed empty charge receiving chamber adapted to be opened as a result of lowering engagement with the closure opening member 36 in the tubular assembly I 0. It is to be understood that the invention is not limited to the use of any particular type or form of charge receiving device or bailer, and that any suitable apparatus of that character may be used within the purview of the invention. A particular and specific form of bailer has been shown merely for the purpose of completeness in describing the invention.

The bailer, generally indicated at 52, comprises a series of threadedly connected sections 53, 54 and 55 (see Fig. 3) section 53 serving as a top closure for the low pressure or charge receiving chamber 56. Section 53 is attached to a suspension element, for example cable 51 by means of which the bailer is raised and lowered in the pipe string I2. Section 54, here shown as longitudinally contracted, may be of any desirable length, although a forty foot length giveg chamber 56 a capacity ample for most operations.

Section 53 has a reduced axial bore 53afrom which extends a transverse passage 58 controlled 'by spring closed, outwardly opening relief valve 59. The function of this valve is merely to relieve high pressure in the charge receiving chamber 56 as the bailer is raised into zones of lower pressure. To facilitate unloading chamber 56, the apertured screw plug 59a threaded into the valve seat 68 may be removed, together with the valve 59, so as to relieve the lowered pressure in chamber 56; (caused by dumping the fluid) by bleeding in air through passage 58. Pressure relief and air bleed valves of this general character for use in well cleaners or bailers, are more particularly dealt with in the copending application of W. C. Erwin et al. on Well bailers,

flied April 22, 1933, Ser. No. 667,439.

A removable dump door 55a is provided in section 55 of the bailer body, the construction and mounting of this door being fully described in said copending application, Ser. No. 667,439, and requiring for present purposes no further description other than to mention its removability to dump the charge from chamber 56 following a cleaning operation and after the bailer has been elevated to the ground surface. Screwed into and depending from section 55 is a tubular section 6|, and seating within this section is a foot valve 62 which raises to permit the upward flow of the charge into chamber 56, and thereafter seats to trap the charge in the chamber for removal from the well. The charge receiving chamber is normally closed at its lower end by a frangible disk 62 clamped between body shoulder 63 and a retaining ring 64 threaded into the lower end of section 6|. The lower end of the body and ring 64 are beveled at 65 at an angle corresponding to the bevel 46b on the upper end of valve 46 in order that when lowered into engagement with the valve, the bailer and valve will have a substantially fluid-tight fit.

In performing a cleaning operation, tubular assembly I0 is firstlowered within the casing on pipe string I2 to the depth of the particular portion of the casingto be cleaned. At this stage,

10 ports ii in communication with space at and the pipe string i2. Continued downward movement of the bailer to the position of Fig. 2 brings disk 62 into engagement with the upper toothed end 3i of the breaking member 36, causing the disk to become broken and the charge receiving chamber 58 of the bailer to be brought into communication, through the disk breaking member 35, with passage til therebelow. it will be urtderstood that the bailer 52 may be lowered rapidly, and that the downward momentum of the trailer at the point at which disk $2 is brought into engagement with the breaking member 36, will be sufilcient to insure rupturing the disk.

Immediately upon breaking the disk, a sudden pressure differential is imposed between the outside and inside of the casing between packers it and it, with the result that there occurs a sudden rush of well fluid through the perforations l3, acting to dislodge and carry into space 28 particles clogging the perforations. The fluid is drawn through openings 58 into-the passage 50, and thence upwardly through the'valve seat 38 and disk breaking member 35 into the charge receiving chamber 55. After the full charge has i been taken in, and a substantial pressure balance exists between the chamber 56 and the formation pressure acting to force the charge into the chamber, valve 62 seats to trap the charge in the boiler. it will be noted that by reason of the engagement between the lower end of the bailer and the upper end of valve to, and between face 460 on the bottom of the valve and shoulder 35a of the disk breaking member, the upward suction into the bailer is through, rather than around the disk breaking member.

I have previously referred to the distinctive characteristic of the invention in producing a downward washing circulation of fluid from the pipe string through the formation around the casing perforations being cleaned, as wellas a direct lateral drawing in of well fiuid from that forma tion. The washing action referred to is made possible by putting space it and the interior of the pipe string i2 into communication with the formation surrounding the section of the casing H between packers i8 and 2E3, via spacing it and ports ll, upon opening of valve 65. Thus immediately after disk t2 has become broken, and with the parts in the positions shown in Fig. 2, the upward suction into the charge receiving chamber applied to the casing perforations i3 between packers it and lit produces, in addition to a lateral inflow of fluid from the surrounding forination through the casing perforations, a circulation of well fluid standing within pipe string i2, downwardly through space 39, then out through ports il, space it and the casing perforations between packers if and it, into the surrounding well sands. The fluid then flows downwardly, flushing and washing through the formation between the levels of packers H and 2B, and is drawn in through perforations it between packers i8 and 2d, along with the well fluid being taken in from that zone.

Thus in addition to cleaning the perforations it, I am able to efiectively open and increase the well production and normal fluid flow through the formation interstitial spaces by reason of the downward washing action of the fluid being drawn from the fluid column standing in the pipe string and the simultaneously induced horizontal cross= fiow'into the perforations from the formation. The arrows at in Fig. 2 indicate the path of fluid flow from the pipe string out through ports d! and space it, and the downward flushing circu lation, indicated by the arrows a; the direction of the horizontal cross-flow being represented by the arrows c.

In order to maintain a maximum fluid head in the pipe string, and thereby increase the effec-= tiveness of the washing fluid circulating down around the casing, the pipe it may, if desired, be filled with liquid to the ground surface, so that upon opening valve 46 and the charge receiving chamber 56, there will exist a mainrnurn pressure differential acting to draw the flushing fluid from space 89 down around the casing and into ports 58.

At the completion of the cleaning operation, the bailer is withdrawn from the well and the charge dumped in the manner previously eirplained. After a new disk 62 has been placed in the bailer, the latter may again be lowered to perform another cleaning operation with the tubular assembly Ill remaining in substantially the same position, or after one or a number of individual cleaning operations, the assembly may be shifted vertically within the casing to bring the packers opposite a successive section of the casing to be cleaned.

I claim:

1. In well cleaning apparatus, the combination comprising a pipelowered within the well casing, a tubular body attached to the lower end of said pipe and having apertures opposite the casing perforations, a packer carried on the body above said apertures, means for draining the liquid column in said pipe above said body outwardly through a port in said body, so that the liquid thence flows out through the casing perforations above said packer, and suction operated means for simultaneously drawing liquid inwardly into the body through the casing perforations below said packer.

2. In well cleaning apparatus, the combination comprising a pipe lowered within the well casing,

a tubular body attached to the lower end of said pipe and having apertures opposite the casin perforations, a pair of packers carried on the body above and below said apertures, means for draining the liquid column in said pipe above said body outwardly through a port in said body, so that the liquid thence flows out through the casing perforations above the upper packer, and suction operated means for simultaneously drawing liquid inwardly into the body through the casing perforations between said packer. r

3, In well cleaning apparatus, the combination comprising a pipe lowered within the well casing, a tubular body attached to the lower end of said pipe and having apertures opposite the casing perforations, a pair of vertically spaced packare carried on the body above said apertures, means for draining the liquid column in said pipe above said body outwardly through a port in said body, so that the liquid thence flows out through the casing perforations between said packers. and suction operated means for simultaneously drawing liquid inwardly into the body through the 4. In well cleaning apparatus, the combination comprising a pipe lowered within the well casing, a tubular body attached to the lower end of said pipe and having apertures opposite the casing perforations, a pair of packers carried on the body above said apertures, a packer on the body below said apertures, and a port through which fluid is discharged from within the body, outwardly between the first mentioned packers.

5. In well cleaning apparatus, the combination comprising a pipe lowered within the well casing, a tubular body attached to the lower end of said pipe and having apertures opposite the casing perforations, a pair of packers carried on the body above said apertures, a packer on the body below said apertures, a port through which fluid is discharged from within the body, outwardly between the first mentioned packers and a valve normally closing said port.

6. In well cleaning apparatus, the combination comprising a pipe lowered within the well casing, a tubular body attached to the lower end of said pipe and having apertures opposite the casing perforations, a pair of packers carried on the body above said apertures, a packer on the body below said apertures, a port through which fluid is discharged from within the body,. outwardly between the first mentioned packers, a valve normally closing said port, said valve being adapted to be opened by engagement with a bailer lowered within said pipe, and yielding means supporting the valve.

7. In well cleaning apparatus, the combination comprising a pipe lowered within the well casing, a tubular body attached to the lower end of said pipe and having apertures opposite the easing perforations, a pair of packers carried on the body above said apertures, a packer on the body below said apertures, a port through which fluid is discharged from within the body, outwardly between the first mentioned packers, a valve normally closing said port, said valve being adapted to be opened by engagement with a bailer lowered within said pipe, yielding means supporting the valve, and a check valve within the body below the last mentioned valve.

8. In well cleaning apparatus, the combination comprising a pipe lowered within the well casing, a tubular body attached to the lower end ofsaid pipe and having apertures opposite the casing perforations, a packer carried on the body above said apertures, means for causing the liquid column in said pipe above said body to flow outwardly through a port in said body and through the casing perforations above said packer, suction operated means for simultaneously drawing liquid inwardly into the body through the casing perforations below said packer, and valve means for controlling the outward flow of fluid through said port.

9. In well cleaning apparatus, the combination comprising a pipe lowered within the well casing, a tubular body attached to the lower end of said pipe and having apertures opposite the casing perforations, a packer carried" on the body above said apertures, means for causing the liquid column in said pipe above said body to fiow outwardly through a port in said body and through the casing perforations above said packer, and thence to be then drawn inwardly into the body through the casing periorations below said packer, and valve means for controlling the outward flow of fluid through said port, said valve means comprising a valve movable vertically within the body, and yielding means supporting the valve.

through the casing perforations above said packer, and thence to be then drawn inwardly into the body through the casing perforations below said packer, and valve means for controlling the outward fiow of fluid through said port, and a bailer closure opening means within said body.

11. In well cleaning apparatus, the combination comprising a pipe lowered within the well casing, a tubular body attached to the lower end of said pipe and having apertures opposite the casing perforations, a packer carried on the body above said apertures, means for causing the liquid column in said pipe above said body to flow outwardly through a port in said body and through the casing perforations above said packer, and thence to be then drawn inwardly into the body through the casing perforations below said packer, and valve means for controlling the outward flow of fiuid through said port, said valve means comprising a tubular valve movable vertically within the body, yielding means supporting the valve, and a bailer closure opening means within said body and in telescopi'ng relation with said valve.

12. In well cleaning apparatus, the combination comprising a pipe lowered within the well casing, a tubular body attached to the lower end of said pipe andhaving apertures opposite the casing perforations, a packer carried on said body above said apertures, a bailer adapted to be lowered within said pipe and having a closure adapted to be opened to admit well liquid to a chamber within the bailer, means on said body cooperating with the bailer to open said closure, and means whereby opening of the closure causes the liquid column in said pipe above said body to fiow outwardly through a body port and the casing perforations above said packer, and to be thence drawn inwardly through the casing perforations below said packer.

13. In well cleaning apparatus, the combination comprising a pipe lowered within the well casing, a tubular body attached .to the lower end of said pipe and having apertures opposite the casing perforations, a packer carried on said body above said apertures, a bailer adapted to be lowered within said pipe and having a closure adapted to be opened to admit well liquid to a chamber within the bailer, means on said body cooperating with the bailer to open said closure, and means whereby opening of the closure causes the liquid column in said pipe above said body to fiow outwardly through a body port and the casing perforations above said packer, and to be thence drawn inwardly through the casing perforations below said packer, and upwardly within said body into the bailer.

14. In well cleaning apparatus, the combination comprising a pipe lowered within the well casing, a tubular body attached to the lower end of said pipe and having apertures opposite the casing perforations, a packer carried on said body above said apertures, a bailer adapted to be lowered within said pipe and having a closure adapted to be opened to admit well liquid to a chamber within the bailer, means on said body cooperating with the bailer to open said closure, means whereby opening of the closure causes the liquid column in said pipe above said body to flow outwardly through a body port and the casing perforations above said packer, and to be thence drawn inwardly through the casing perforations below said packer, and a valve normally closing said port and adapted to be opened by engagement by said bailer.

15. In well cleaning apparatus, the combination comprising a pipe lowered within the well casing, a tubular body attached to the lower end of said pipe and having apertures opposite the casing perforations, a packer carried on said body above said apertures a bailer adapted to be lowered within said pipe and having a closure adapted to be opened to admit well liquid to a chamber within the bailer, means whereby opening of the closure causes the liquid column in said pipe above said body to flow outwardly through a body port and the casing perforations above said packer, and to be thence drawn inwardly through the casing perforations below said packer, a tubular valve normally closing said port and adapted to be moved downwardly by engagement by the bailer to open the port, yielding means supporting said valve, and a bailer closure opening means projecting upwardly within the body in telescoping relation with said valve.

CECIL H. SWEET. 

